1. Field of the Invention
The present invention relates to a coordinates correction apparatus including a coordinates input area for correcting the received coordinates of a location optionally indicated on the coordinates input area, a coordinates correction method, and a memory medium that can be read by a computer storing a control program for the coordinates correction process.
The present invention also relates to a coordinates correction parameter calculation apparatus for calculating coordinates correction parameters for correcting the coordinates of a location optionally indicated on the coordinates input area, a coordinates correction parameter calculation method, and a memory medium that can be read by a computer storing a program for performing coordinates correction parameter calculation.
2. Related Background Art
Conventionally, for correction of input coordinates in coordinates input apparatuses, a method has been employed in which coordinates correction parameters are calculated by solving simultaneous equations expressed by linear conversion from the raw coordinate values obtained from several locations used as reference points on the coordinates input area of the coordinates input apparatus, substituting the input coordinates into the linear conversion formulas, as shown in Japanese Patent Application Laid-Open Nos. 5-313822 and 8-171451 and Japanese Patent No. 2,517,664.
Such a correction parameter calculation method is described below. First, two reference points (X0, Y0) and (X1, Y1) are set on the coordinates input area of the coordinates input apparatus and the position of those reference points are indicated with a mark. These indicators are displayed on a display apparatus such as a liquid crystal display installed under a transparent coordinates input area, for example. Next, raw coordinates data for two points are input from a coordinates input apparatus when the user points to the position at which the user sees the marks by eye (for example using an indication tool for coordinates input in the form of a pen). The input raw coordinates data (xnw, ynw) and (xse, yse) will form the following relationship with the original coordinates of the two standard points.                                           X            0                    =                                    a              ⁢                                                           ⁢                              x                                  n                  ⁢                                                                           ⁢                  w                                                      +            b                          ⁢                                  ⁢                              Y            0                    =                                    c              ⁢                                                           ⁢                              y                                  n                  ⁢                                                                           ⁢                  w                                                      +            d                          ⁢                                  ⁢                              X            1                    =                                    a              ⁢                                                           ⁢                              x                                  s                  ⁢                                                                           ⁢                  e                                                      +            b                          ⁢                                  ⁢                              Y            1                    =                                    c              ⁢                                                           ⁢                              y                                  s                  ⁢                                                                           ⁢                  e                                                      +            d                                              [                  Equation          ⁢                                           ⁢          1                ]            
(a, b, c, and d are constants)Correction parameters a, b, c, and d are found from the formulas as follows.                               a          =                                                    X                1                            -                              X                0                                                                    x                                  s                  ⁢                                                                           ⁢                  e                                            -                              x                                  n                  ⁢                                                                           ⁢                  w                                                                    ⁢                                  ⁢                  b          =                                                                      X                  0                                ⁢                                  x                                      s                    ⁢                                                                                   ⁢                    e                                                              -                                                X                  1                                ⁢                                  x                                      n                    ⁢                                                                                   ⁢                    w                                                                                                      x                                  s                  ⁢                                                                           ⁢                  e                                            -                              x                                  n                  ⁢                                                                           ⁢                  w                                                                    ⁢                                  ⁢                  c          =                                                    Y                1                            -                              Y                0                                                                    y                                  s                  ⁢                                                                           ⁢                  e                                            -                              y                                  n                  ⁢                                                                           ⁢                  w                                                                    ⁢                                  ⁢                  d          =                                                                      Y                  0                                ⁢                                  y                                      s                    ⁢                                                                                   ⁢                    e                                                              -                                                Y                  1                                ⁢                                  y                                      n                    ⁢                                                                                   ⁢                    w                                                                                                      y                                  s                  ⁢                                                                           ⁢                  e                                            -                              y                                  n                  ⁢                                                                           ⁢                  w                                                                                        [                  Equation          ⁢                                           ⁢          2                ]            Calculating the parameters as above and using them for correction of the input coordinates is effective when the coordinates detection characteristic of the coordinates input apparatus is parallel to the X-axis and the Y-axis. However, in general there is often in incline with respect to the axis. Thus, a correction method was also conceived of using three reference points (X0, Y0), (X1, Y1) and (X2, Y2) where the relationship between the raw coordinates data is as follows:                                           X            0                    =                                    a              ⁢                                                           ⁢                              x                                  n                  ⁢                                                                           ⁢                  w                                                      +                          b              ⁢                                                           ⁢                              y                                  n                  ⁢                                                                           ⁢                  w                                                      +            c                          ⁢                                  ⁢                              Y            0                    =                                    d              ⁢                                                           ⁢                              x                                  n                  ⁢                                                                           ⁢                  w                                                      +                          e              ⁢                                                           ⁢                              y                                  n                  ⁢                                                                           ⁢                  w                                                      +            f                          ⁢                                  ⁢                              X            1                    =                                    a              ⁢                                                           ⁢                              x                                  s                  ⁢                                                                           ⁢                  e                                                      +                          b              ⁢                                                           ⁢                              y                                  s                  ⁢                                                                           ⁢                  e                                                      +            c                          ⁢                                  ⁢                              Y            1                    =                                    d              ⁢                                                           ⁢                              x                                  s                  ⁢                                                                           ⁢                  e                                                      +                          e              ⁢                                                           ⁢                              y                                  s                  ⁢                                                                           ⁢                  e                                                      +            f                          ⁢                                  ⁢                              X            2                    =                                    a              ⁢                                                           ⁢                              x                                  n                  ⁢                                                                           ⁢                  e                                                      +                          b              ⁢                                                           ⁢                              y                                  n                  ⁢                                                                           ⁢                  e                                                      +            c                          ⁢                                  ⁢                              Y            2                    =                                    d              ⁢                                                           ⁢                              x                                  n                  ⁢                                                                           ⁢                  e                                                      +                          e              ⁢                                                           ⁢                              y                                  n                  ⁢                                                                           ⁢                  e                                                      +            f                                              [                  Equation          ⁢                                           ⁢          3                ]            
(a, b, c, d, e, and f are constants)
The correction parameters a, b, c, d, e, and f are found from the following formulas.                               a          =                                                                      (                                                            X                      2                                        -                                          X                      0                                                        )                                ⁢                                  (                                                            y                                              s                        ⁢                                                                                                   ⁢                        e                                                              -                                          y                                              n                        ⁢                                                                                                   ⁢                        w                                                                              )                                            -                                                (                                                            X                      1                                        -                                          X                      0                                                        )                                ⁢                                  (                                                            y                                              n                        ⁢                                                                                                   ⁢                        e                                                              -                                          y                                              n                        ⁢                                                                                                   ⁢                        w                                                                              )                                                                                                      (                                                            x                                              n                        ⁢                                                                                                   ⁢                        e                                                              -                                          x                                              n                        ⁢                                                                                                   ⁢                        w                                                                              )                                ⁢                                  (                                                            y                                              s                        ⁢                                                                                                   ⁢                        e                                                              -                                          y                                              n                        ⁢                                                                                                   ⁢                        w                                                                              )                                            -                                                (                                                            x                                              s                        ⁢                                                                                                   ⁢                        e                                                              -                                          x                                              n                        ⁢                                                                                                   ⁢                        w                                                                              )                                ⁢                                  (                                                            y                                              n                        ⁢                                                                                                   ⁢                        e                                                              -                                          y                                              n                        ⁢                                                                                                   ⁢                        w                                                                              )                                                                    ⁢                                  ⁢                  b          =                                                                      (                                                            X                      2                                        -                                          X                      0                                                        )                                ⁢                                  (                                                            x                                              s                        ⁢                                                                                                   ⁢                        e                                                              -                                          x                                              n                        ⁢                                                                                                   ⁢                        w                                                                              )                                            -                                                (                                                            X                      1                                        -                                          X                      0                                                        )                                ⁢                                  (                                                            x                                              n                        ⁢                                                                                                   ⁢                        e                                                              -                                          x                                              n                        ⁢                                                                                                   ⁢                        w                                                                              )                                                                                                      (                                                            y                                              n                        ⁢                                                                                                   ⁢                        e                                                              -                                          y                                              n                        ⁢                                                                                                   ⁢                        w                                                                              )                                ⁢                                  (                                                            x                                              s                        ⁢                                                                                                   ⁢                        e                                                              -                                          x                                              n                        ⁢                                                                                                   ⁢                        w                                                                              )                                            -                                                (                                                            y                                              s                        ⁢                                                                                                   ⁢                        e                                                              -                                          y                                              n                        ⁢                                                                                                   ⁢                        w                                                                              )                                ⁢                                  (                                                            x                                              n                        ⁢                                                                                                   ⁢                        e                                                              -                                          x                                              n                        ⁢                                                                                                   ⁢                        w                                                                              )                                                                    ⁢                                  ⁢                  c          =                                    X              0                        -                          a              ⁢                                                           ⁢                              x                                  n                  ⁢                                                                           ⁢                  w                                                      -                          b              ⁢                                                           ⁢                              y                                  n                  ⁢                                                                           ⁢                  w                                                                    ⁢                                  ⁢                  d          =                                                                      (                                                            Y                      2                                        -                                          Y                      0                                                        )                                ⁢                                  (                                                            y                                              s                        ⁢                                                                                                   ⁢                        e                                                              -                                          y                                              n                        ⁢                                                                                                   ⁢                        w                                                                              )                                            -                                                (                                                            Y                      1                                        -                                          Y                      0                                                        )                                ⁢                                  (                                                            y                                              n                        ⁢                                                                                                   ⁢                        e                                                              -                                          y                                              n                        ⁢                                                                                                   ⁢                        w                                                                              )                                                                                                      (                                                            x                                              n                        ⁢                                                                                                   ⁢                        e                                                              -                                          x                                              n                        ⁢                                                                                                   ⁢                        w                                                                              )                                ⁢                                  (                                                            y                                              s                        ⁢                                                                                                   ⁢                        e                                                              -                                          y                                              n                        ⁢                                                                                                   ⁢                        w                                                                              )                                            -                                                (                                                            x                                              s                        ⁢                                                                                                   ⁢                        e                                                              -                                          x                                              n                        ⁢                                                                                                   ⁢                        w                                                                              )                                ⁢                                  (                                                            y                                              n                        ⁢                                                                                                   ⁢                        e                                                              -                                          y                                              n                        ⁢                                                                                                   ⁢                        w                                                                              )                                                                    ⁢                                  ⁢                  e          =                                                                      (                                                            Y                      2                                        -                                          Y                      0                                                        )                                ⁢                                  (                                                            x                                              s                        ⁢                                                                                                   ⁢                        e                                                              -                                          x                                              n                        ⁢                                                                                                   ⁢                        w                                                                              )                                            -                                                (                                                            Y                      1                                        -                                          Y                      0                                                        )                                ⁢                                  (                                                            x                                              n                        ⁢                                                                                                   ⁢                        e                                                              -                                          x                                              n                        ⁢                                                                                                   ⁢                        w                                                                              )                                                                                                      (                                                            y                                              n                        ⁢                                                                                                   ⁢                        e                                                              -                                          y                                              n                        ⁢                                                                                                   ⁢                        w                                                                              )                                ⁢                                  (                                                            x                                              s                        ⁢                                                                                                   ⁢                        e                                                              -                                          x                                              n                        ⁢                                                                                                   ⁢                        w                                                                              )                                            -                                                (                                                            y                                              s                        ⁢                                                                                                   ⁢                        e                                                              -                                          y                                              n                        ⁢                                                                                                   ⁢                        w                                                                              )                                ⁢                                  (                                                            x                                              n                        ⁢                                                                                                   ⁢                        e                                                              -                                          x                                              n                        ⁢                                                                                                   ⁢                        w                                                                              )                                                                    ⁢                                  ⁢                  f          =                                    Y              0                        -                          dx              nw                        -                          ey              nw                                                          [                  Equation          ⁢                                           ⁢          4                ]            
When these coordinates correction parameters are established, the input coordinates are corrected based on the formulas below, and output to, for example, a liquid crystal display serving as a coordinates output means.
After finding the correction parameters, when the coordinates are actually input, the correction formulas are expressed as:X=ax+bY=cx+dusing the correction parameters a, b, c, and d when there are two reference points in the correction method using two reference points. When using the correction method having three reference points, the formulas are expressed:X=ax+by=CY=dx+ey+fusing correction parameters a, b, c, d, e, and f.
Further, in Japanese Patent Application Laid-Open No. 8-171451, in order to compensate for the nonlinear characteristic of the coordinates input apparatus, an embodiment is disclosed in which the territory is finely divided by 20 reference points and the correction parameters are sought for each territory through the method of seeking the correction parameters with three reference points.